You can’t manage what you don’t measure. This fundamental maintenance rule applies as much to wind turbines as to any other moving machinery. Happily, there is a way to analyse these assets to predict likely breakdowns before they occur. Fabrice Drommi, Business Development Manager, condition-based maintenance in wind at SKF, explains.

Gothenburg, Sweden, 26 April 2018: Just about every corporate indicator – from safety and environmental performance to financial strength – improves if you establish reliability as a core organisational value. Although this applies in all business areas, nowhere is reliability more vital than in companies operating machinery with moving parts – wind farms, for example. 

However, the harder machinery works and the older it gets, the less reliable it tends to become. This is where condition monitoring (CM) can make a significant positive difference. The benefits of CM on any machine with rotating components are remarkable, but the advantages are particularly compelling in wind turbine applications, especially when combined with remote monitoring and diagnostics. 

CM is essentially a strategy that monitors the condition of an asset to decide what maintenance needs to be done based on signs of decreasing performance or approaching failure. Typically, it involves measuring parameters of the machine being monitored, such as vibration and temperature 

By alerting the maintenance team to significant changes in one or more of these parameters (which is indicative of a developing fault), CM can virtually eliminate unscheduled downtime caused by unexpected machine failure. 

In wind turbine applications, it can save vast amounts of money by allowing the wind farm operator to repair tower components in-situ instead of having to go through the expense and disruption of dismantling them and taking them to a warehouse to be fixed. 

Secondly and directly related to this, it is far less expensive to correct faults and fix damage at an early stage of degradation rather than later on when the components might need to be replaced completely. 

Thirdly, CM ensures the turbines are operating at their optimum performance level and makes certain servicing is carried out only when the machine actually needs attention. 

So CM is less costly than taking action only when plant fails, and helps maintain energy efficiency and maximise machine productivity, saving even more. 

But its benefits don’t end there. CM can also help lengthen component life, extend overhaul intervals, enhance safety, shorten repair time and increase the wind turbine’s life. It really is an obvious choice – CM on wind farms makes solid business sense. This, however, begs a fundamental question – how can a wind farm operator perform CM effectively? The answer is simpler than you might imagine. You need to select the best CM solution which, in this context, means technology and services. 

The first issue to consider is the complexity of the application. If you have a simple machine, simple CM technology should normally fit. If it is more complex, of course, you will need a more sophisticated CM system. 

The second point is to consider how quickly the degradation might occur. If the fault is likely to develop slowly, you have time to take measurements and respond. However, should the degradation occur quickly then catastrophic failure is possible, leaving no time to react. In these circumstances, it makes sense to install permanent or online CM measures which can detect a fault before it leads to disaster. 

The third point is accessibility. In the case of a wind turbine, if somebody has to climb every time they need to take readings, this exposes them to unnecessary risk. Here, it makes sense to install an ‘intelligent’ system which takes measurements only when the machine is rotating at a defined load level, and which can be read remotely. 

To be truly effective, CM requires a regular flow of monitored data. SKF, for example, offers a complete system of monitoring, analysis and diagnostics and the knowledge around the application itself needed to improve the reliability of the asset. 

Indeed, SKF delivers design and development of bearings, seals, condition monitoring systems, and lubrication systems that enable more cost-effective wind energy generation. 

Working with original equipment manufacturers and wind farm operators, SKF engineers can provide dedicated solutions that can optimise the reliability and performance of new and existing wind turbine designs. 

Sensors for wind turbine applications can be wired to the IMx-8 system which measures the vibration levels of wind turbines 24/7 to anticipate any mechanical issues that could occur in future. The logging system then measures and stores the data, so that a dedicated SKF team can evaluate what needs to be done when an alarm occurs. 

The book-sized IMx-8 interfaces with mobile devices and laptops for easy monitoring and setup. It can connect with SKF’s Cloud service for storing and sharing data, and to SKF’s remote monitoring service. The remote monitoring service means any company with internet access can implement a predictive maintenance programme for monitoring critical machinery. SKF can manage the entire monitoring programme or put together a custom infrastructure as a turnkey system for a company to operate on its own. 

Finally, software is needed to diagnose problems once they have been detected. In our case, this can be done by Enlight, our Cloud-based, next generation software which performs data collection, review and analysis. Data can be sent from the wind farms to our data centre for analysis using a virtual private network. 

SKF Enlight combines the intuitive ease of use of iOS or Android app running on a standard mobile device with the power to access customised workflows for specific tasks, and the ability to collect data from a wide range of sources and sensors.